Fitness experts look at those core beliefs

Working for the six-pack may be a superficial goal. (Getty Images / Uppercut…)

Of all of the muscles in the body, the ones in the midsection get an outsized share of attention. They even have their own brand name: "the core." As in core workouts, core training and core strength.

The core is a hot commodity right now because it supports some of the fundamental ideals of our culture: athletic ability, attractiveness and, not least, our birthright as Americans to spend a lot of money on exercise DVDs and workout machines. The core has also become a focal point for baby boomers hoping to hold on to their strength and flexibility. Maintain the core, the theory goes, and the body will follow.

Core muscles do, in fact, play a fundamental role in athletic performance and overall health, says Stuart McGill, a professor of kinesiology and the director of the spine biomechanics laboratory at the University of Waterloo in Ontario, Canada. But in his view, the whole concept of the "core" has gotten out of hand, especially when it comes to training devices and other attempts to commercialize core workouts. "There is a lot of nonsense out there," he says. "Core training is a fad."

Whether you're a serious athlete or just a person who wants to get the most out of your body, you'll want to take care of your core. And the task may be simpler than you think, says Thomas Nesser, an associate professor of physical education at Indiana State University in Terre Haute. "A lot of personal trainers make their money with 30-minute core training programs, but you don't need that," he says. He also advises steering clear of gimmicky exercises you can find on the Internet. "You don't need to be half-hanging off a bench and twisting dumbbells," Nesser says.

As McGill explains, core muscles help keep the torso still and steady when you run, jump or lift. This transfers power from your legs to your upper body. Trying to move that muscle power through a weak, floppy core, he says, is like trying to push a limp rope. The core muscles also help protect and support the spine, he adds, making them an important defense against back pain and injury.

McGill works with many National Football League players and other athletes who are hoping to gain an edge through their cores. But he stresses that a strong midsection is important in everyday life too. "Picking up a child out of a crib at 2 in the morning — that can be a nasty lift," he says.

You don't need fancy equipment to work your core, says James Schoffstall, director of exercise science at Liberty University in Lynchburg, Va. Schoffstall is the coauthor of a 2010 study in the Journal of Strength and Conditioning Research that measured muscle activity during various core exercises. The study found that exercises using equipment such as the Power Wheel (a wheel with handles that adds extra challenge to push-ups and other routines) or sliding boards didn't really fire up the abdominal muscles any more than classic exercises such as crunches.

But crunches aren't all they're cracked up to be, Nesser says. The workout mainly just tones the muscles at the very front of the abdomen, making the results superficial in every sense of the word. "People think that ripped abs are a sign of a strong core, but that's not the case," he says. "A six-pack means you've worked those particular muscles so you can look good at the beach."

McGill warns that crunches and sit-ups can put dangerous stress on the spine, especially for people who don't have a wiry physique. "You can find a guy on the Internet who can do 3,000 sit-ups. I can tell you without even looking that he's small and slender. You can bend a thin rod many times and it won't break. A thicker rod breaks quickly. NFL players can't do that many sit-ups."

Whichever core exercises a person chooses, Nesser says, it's important to continue working out the rest of the body too. "The core develops as the rest of your body develops. If someone has a weak core, they probably have a weak body."